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authorKeshavamurthy Anil S <anil.s.keshavamurthy@intel.com>2005-09-06 15:19:35 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-07 16:58:01 -0700
commitdeac66ae454cacf942c051b86d9232af546fb187 (patch)
tree17a72e7a2dcf2d1a93a6afdef661f290b1888f1c /kernel
parentbce0649417d6e71f6df8ab7b11103d247913b142 (diff)
downloadop-kernel-dev-deac66ae454cacf942c051b86d9232af546fb187.zip
op-kernel-dev-deac66ae454cacf942c051b86d9232af546fb187.tar.gz
[PATCH] kprobes: fix bug when probed on task and isr functions
This patch fixes a race condition where in system used to hang or sometime crash within minutes when kprobes are inserted on ISR routine and a task routine. The fix has been stress tested on i386, ia64, pp64 and on x86_64. To reproduce the problem insert kprobes on schedule() and do_IRQ() functions and you should see hang or system crash. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3b7653f..f3ea492 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -155,14 +155,36 @@ void __kprobes free_insn_slot(kprobe_opcode_t *slot)
/* Locks kprobe: irqs must be disabled */
void __kprobes lock_kprobes(void)
{
+ unsigned long flags = 0;
+
+ /* Avoiding local interrupts to happen right after we take the kprobe_lock
+ * and before we get a chance to update kprobe_cpu, this to prevent
+ * deadlock when we have a kprobe on ISR routine and a kprobe on task
+ * routine
+ */
+ local_irq_save(flags);
+
spin_lock(&kprobe_lock);
kprobe_cpu = smp_processor_id();
+
+ local_irq_restore(flags);
}
void __kprobes unlock_kprobes(void)
{
+ unsigned long flags = 0;
+
+ /* Avoiding local interrupts to happen right after we update
+ * kprobe_cpu and before we get a a chance to release kprobe_lock,
+ * this to prevent deadlock when we have a kprobe on ISR routine and
+ * a kprobe on task routine
+ */
+ local_irq_save(flags);
+
kprobe_cpu = NR_CPUS;
spin_unlock(&kprobe_lock);
+
+ local_irq_restore(flags);
}
/* You have to be holding the kprobe_lock */
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